To remove water from the patient, as is generally necessary, other solutes may be added to generate the necessary osmotic pressure. Typically, this solute is a sugar such as glucose, which may normally be present in peritoneal dialysis solutions in a concentration of at least 0.5 percent by weight. When it is desired to increase the ultrafiltration of water from the patient, higher concentrations of sugar are used.
However, as a disadvantage of this system, during the peritoneal dialysis process, as water diffuses into the peritoneal dialysis solution, sugar present in the peritoneal dialysis solution diffuses into the bloodstream to a significant extent. Accordingly, while the system is safe and effective for increasing the ultrafiltration during peritoneal dialysis, it has certain disadvantages. For example, since the sugar diffuses relatively rapidly from the solution in the peritoneal cavity into the bloodstream, there is a considerable and rapid decrease in the osmolarity of the peritoneal dialysis solution. Accordingly, to obtain the desired amount of ultrafiltration, the initial concentration of sugar in the peritoneal dialysis solution must be relatively high to account for the fact that the osmolarity will fall by diffusion of sugar into the bloodstream.
Particularly in certain pediatric cases, children who are on a CAPD regime often lose significant appetite and fail to adequately gain weight. Accordingly it becomes desirable to administer substantial amounts of calories to the child. In accordance with this invention, desired calories can be administered to the pediatric patient while at the same time excessive concentrations of sugar per se are avoided. Such excessive concentrations of sugar could, of course, unduly raise the osmolarity of the solution and would provide undesirable levels of ultrafiltration to the patient. By this invention, the administration of substantial amounts of calories to the patient can be effected by diffusion from the peritoneal dialysis solution, simultaneously with the maintenance of a desired ultrafiltration rate, and also clearance of metabolic waste products such as urea and creatinine through the peritoneal cavity into the dialysis solution. By a proper balance between sugar and other ingredients as described in this invention in a peritoneal dialysis solution, a proper balance of calories, coupled with a proper rate of ultrafiltration can be provided.
In Ramsay et al. U.S. Pat. No. 4,182,756, it is suggested to use high calorie solutions of low molecular weight glucose polymer mixtures in intravenous administration, since such solutions can provide significant increases in calories per liter over monomeric sugar solutions without being hypertonic. Other related prior art is cited in the same patent.
Milner U.S. Pat. No. 3,928,135 also discusses glucose polymers as ingredients for oral ingestion or intravenous administration.
Seifter et al. U.S. Pat. No. 3,911,915 teaches the dialytic introduction of maltose (a disaccharide) intraperitoneally into warm blooded animals. However, maltose shares in the disadvantages of glucose in that the addition of substantial amounts thereof can result in significant and excessive osmolarity so that inadequate amounts of calories may be provided to the pediatric patient by the peritoneal dialysis route, if the osmolarity is proper.